PL79646B2 - - Google Patents

Description

Priority: Application announced: 02/05/1974 Patent description was published: 09/09/1975 79646 U. 40b, 21/04 MKP C22c 21/04 Inventors: Czeslaw Adamski, Zbigniew Bonderek, Tadeusz Piwowarczyk, Stanislaw Banas Authorized by a temporary patent: AGH University of Science and Technology them. St Staszica, Kraków (Poland) A modifying-refining agent for supereutectic aluminum-silicon alloys. The subject of the invention is a modifying-refining agent used in the technology of preparation of super-eutectic aluminum alloys - silicon. Currently, in the technological process of preparation of liquid supereutectic aluminum-silicon alloys, it is used separately first refiners, then gas, powder or tablet modifiers. The refiners used are: hexachloroethane or a mixture of salts; sodium chloride, sodium fluoride, potassium chloride and others. On the other hand, the following modifiers are used: red phosphorus, phosphorus pentachloride or a mixture of phosphorus and sulfur. The disadvantage of this method is that the refining process and the process of modification of supersutectic aluminum-silicon alloys are carried out separately. Moreover, the refiners and modifiers show a low intensity of the refining and modification process, resulting in poor quality of castings and ingots. The aim of the invention is to remedy the above drawbacks. This goal was achieved thanks to the use as a refining - modifying agent, a mixture containing: 30 - 75% by weight of potassium hexafluorozirconate, 10 - 25% by weight of red phosphorus and 10t 28% by weight of hexachloroethane. The advantage of the modifying-refining agent is that it has a modifying effect on both the crystallization of primary silicon and the eutectic matrix in hypereutectic aluminum-silicon alloys, while also having a refining effect. Thanks to the use of the agent, a very strong degassing of the metal bath is obtained, which increases the mechanical properties of the alloy. According to the invention, the modifying-refining agent is introduced into the liquid alloy in a powdered state in the amount of 0.20 * 2% of the weight of the metal charge. All components have a clearance of 0.1 -r3mm. The agent can also be introduced into the liquid metal after pressing into pellets. Potassium hexafluoro-zirconate at elevated temperatures, reacting with aluminum, has a refining effect, and the zirconium compounds formed as a result of the reaction, such as: aluminum zirconate, zirconium carbide and others, have a modifying effect on the structure of the alloy. Red phosphorus is introduced mainly to modify the primary silicon grains. Hexachloroethane removes alumina from the bath and degasses it, and at the same time intensifies the process of alloy modification.2 79 646 Example: Modifying and refining agent with the composition given in percent by weight: potassium hexafluorocirconate 60% K2ZrF6 red phosphorus 18% P hexachloroethane 22% C2 Cl6 in the amount of 0.8% of the mass of the metal charge, the superutectic aluminum-silicon alloy ASi 20 CuNi is added. As a result, the alloy shows a significant increase in mechanical properties in relation to the properties of the alloy modified with previously known mixtures namely: resistance to solution Rm - 20.2 kG / mm2 elongation A5 - 3.4% Brinella HB hardness -99.5 kG / mm2 primary silicon grain size - 12.4 μm In contrast, the superutectic aluminum-silicon alloy, modified with known means, shows the following mechanical properties: tensile strength Rm - 16.6 kG / mm2 elongation A5 - 1,33% hardness Brinella HB - 105 kG / mm2 primary silicon grain size - 23 / im PL PL

Claims (1)

1. Patent claim An agent modifying and refining superutectic aluminum-silicon alloys, containing red phosphorus and hexachloroetah, characterized by a mixture containing 30 -s- 75% by weight of potassium hexafluorocyronate, 10 t 25% by weight red phosphorus and 10 - s- 28 wt.% hexachloroethane. Wash. Poligraf, UP PRL. Order 2984/75. Mintage 120 + 18, Price 10 PLN PL PL